Combination of multiple analytical platforms and nontargeted approaches for comprehensive risk assessment characterization: thirdhand tobacco smoke as case study

摘要

Aim: To the date, most of the risk assessment studies are focused on the determination of specific families of toxicants in different environmental matrices and the evaluation of the human health risk associated to this exposure. Nevertheless, the risk associated to complex matrices exposure, such as indoor dust, which contains hundreds of contaminants, may lead to possible mixture-related effects - such as, antagonistic, synergistic, potentiating or additive effects - that are underestimated in targeted studies. Here, we evaluate the benefits of using different analytical platforms to achieve a more complete identification of the hazardous composition of complex environmental samples for a more holistic characterization of the human risk through the exposure to these contaminants. The developed methodology is applied to the risk evaluation of dust samples from smokers' and non-smokers' homes polluted with residual tobacco smoke, also so-called, thirdhand tobacco smoke (THS). Tobacco smoke is considered one of the major sources of inorganic and organic carcinogens in indoor environments, but more evidence of the chemical toxicity of THS and its impact on human health is necessary to improve understanding of the risks of THS-polluted environments. Methods: We have extracted indoor dust samples from smokers' and non-smokers' homes using pressurized liquid extraction and ethyl acetate as solvent. We have used three different analytical platforms to analyze these extracts, including single and comprehensive gas chromatography (GC-QTOF and GCxGC-TOF) and liquid chromatography (UPLC-QTOF). The raw data have been processed using in-house and commercial software programs. Univariate and multivariate statistical analysis have been used for feature selection to better profile THS toxicants. Results: The use of multiple analytical platforms allowed a more complete identification of the toxicological profile of THS. GCxGC-TOF, with enhanced separation power, provided a visual profiling of the samples and allowed the classification of the toxicants by chemical group. GC-QTOF, which provided the exact mass of the ions, favored the identification of the contaminants. UHPLC-QTOF is complementary to GC and permitted the identification of polar and semivolatile contaminants. The putative identification of the main contaminants was confirmed with the MS/MS spectrum and the use of compound standards. Conclusions: The results presented here demonstrate the benefits of using multiple analytical platforms and non-targeted approaches to achieve a more comprehensive risk assessment of complex environmental mixtures. The application of this holistic methodology in future studies will help to better understand the chemical risk of polluted environments.